2007 CHEVROLET EXPRESS transmission

The vehicle has a shift stabilization feature that adjusts
the transmission shifting to the current driving
conditions in order to reduce rapid upshifts and
downshifts. This shift stabilization feature is designed to
determine, before making an upshift, if the engine is
able to maintain vehicle speed by analyzing things such
as vehicle speed, throttle position, and vehicle load.
If the shift stabilization feature determines that a current
vehicle speed cannot be maintained, the transmission
does not upshift and instead holds the current gear.
In some cases, this could appear to be a delayed shift,
however the transmission is operating normally.
The transmission uses adaptive shift controls. Adaptive
shift controls continually compares key shift parameters
to pre-programmed ideal shifts stored in the
transmissions computer. The transmission constantly
makes adjustments to improve vehicle performance
according to how the vehicle is being used, such as with
a heavy load or when temperature changes. During this
adaptive shift control process, shifting might feel different
as the transmission determines the best settings.
The shift quality of a new vehicle may not be ideal
because the Adaptive Shift Control process may not
have determined the best settings for a particular shift or
condition. Shift quality will improve with continued
driving.When temperatures are very cold, the transmission’s
gear shifting could be delayed providing more stable
shifts until the engine warms up. Shifts could be more
noticeable with a cold transmission. This difference
in shifting is normal.
M (Manual Mode):This position lets drivers select
the range of gears appropriate for current driving
conditions. If the vehicle has this feature, see Range
Select Mode later in this section.
3 (Third):This position is also used for normal driving.
It reduces vehicle speed more than D (Drive) without
using the brakes. You might choose 3 (Third) instead of
D (Drive) when driving on hilly, winding roads, when
towing a trailer, so there is less shifting between gears
and when going down a steep hill. See Range Select
Mode later in this section.
2 (Second):This position reduces vehicle speed even
more than 3 (Third) without using the brakes. You
can use 2 (Second) on hills. It can help control vehicle
speed as you go down steep mountain roads, but
then you would also want to use the brakes off and on.
See Range Select Mode later in this section.
If you manually select 2 (Second) in an automatic
transmission, the transmission will start in second gear.
You can use this feature for reducing the speed of
the rear wheels when you are trying to start the vehicle
from a stop on slippery road surfaces.
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1 (First):This position reduces vehicle speed without
using the brakes. You can use it for major/severe
downgrades where the vehicle would otherwise
accelerate due to steepness of grade. When you shift to
1 (First) it provides the lowest gear appropriate to
current road speed and continues to downshift as the
vehicle slows, eventually downshifting to 1 (First)
gear. The transmission can be held in 1 (First) gear
using Range Select Mode or the shift lever. See Range
Select Mode later in this section.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by the vehicle warranty. If you
are stuck, do not spin the tires. When stopping on a
hill, use the brakes to hold the vehicle in place.Range Selection Mode
The vehicle may have a Range Selection Mode. The
Range Selection Mode helps control the vehicle’s
transmission and vehicle speed while driving down hill
or towing a trailer by letting you select a desired range of
gears.
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To use this feature, do the following:
1. Move the shift lever to M (Manual Mode).
2. Press the plus/minus buttons, located on the
steering column shift lever, to select the desired
range of gears for current driving conditions.
When M (Manual Mode) is selected a number displays
in the DIC next to the M indicating the current gear.
This number is the highest gear that can be used.
However, the vehicle can automatically shift to lower
gears as it adjusts to driving conditions. This means that
all gears below that number are available. When
5 (Fifth) is selected, 1 (First) through 5 (Fifth) gears are
automatically shifted by the vehicle, but 6 (Sixth)
cannot be used until the plus/minus button located on
the steering column lever is used to change to the gear.
Grade Braking is not available when Range Selection
Mode is active. SeeTow/Haul Mode on page 3-34.While using Range Selection Mode, cruise control and
the Tow/Haul mode can be used.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by the vehicle warranty. If you
are stuck, do not spin the tires. When stopping on a
hill, use the brakes to hold the vehicle in place.
Low Traction Mode
Low Traction Mode can assist in vehicle acceleration
when road conditions are slippery. While the vehicle is at
a stop, select the second gear range using Range
Selection Mode. This will limit torque to the wheels after
it detects wheel slip, preventing the tires from spinning.
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Automatic Transmission Operation
(Four Speed Automatic
Transmission)
There are several different positions for your shift lever.
P (Park):This position locks your rear wheels. It is
the best position to use when you start the engine
because the vehicle cannot move easily.
{WARNING:
It is dangerous to get out of the vehicle if the shift
lever is not fully in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the vehicle when the engine is
running unless you have to. If you have left the
engine running, the vehicle can move suddenly.
You or others could be injured. To be sure the
vehicle will not move, even when you are on fairly
level ground, always set the parking brake and
move the shift lever to P (Park). SeeShifting Into
Park on page 3-37. If you are pulling a trailer, see
Towing a Trailer on page 5-30.
Make sure the shift lever is fully in P (Park) before
starting the engine. The vehicle has an automatic
transmission shift lock control system. You must first
press the brake pedal before you can shift from P (Park)
with the ignition in ON/RUN.
If you cannot shift out of P (Park), ease pressure on the
shift lever and push the shift lever all the way into
P (Park) as you maintain brake application. Then move
the shift lever into another gear. SeeShifting Out of
Park on page 3-38.
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R (Reverse):Use this gear to back up.
Notice:Shifting to R (Reverse) while the vehicle is
moving forward could damage the transmission.
The repairs would not be covered by the vehicle
warranty. Shift to R (Reverse) only after the vehicle
is stopped.
To rock the vehicle back and forth to get out of snow,
ice or sand without damaging the transmission, see
If Your Vehicle is Stuck in Sand, Mud, Ice, or Snow on
page 5-18.
N (Neutral):In this position, the engine does not
connect with the wheels. To restart the engine when the
vehicle is already moving, use N (Neutral) only. Also,
use N (Neutral) when the vehicle is being towed.
{WARNING:
Shifting into a drive gear while the engine is
running at high speed is dangerous. Unless your
foot is firmly on the brake pedal, the vehicle could
move very rapidly. You could lose control and hit
people or objects. Do not shift into a drive gear
while the engine is running at high speed.Notice:Shifting out of P (Park) or N (Neutral) with
the engine running at high speed may damage
the transmission. The repairs would not be covered
by the vehicle warranty. Be sure the engine is
not running at high speed when shifting the vehicle.
D (Drive):This position is for normal driving. It
provides the best fuel economy. If you need more
power for passing, and you are:
•Going less than about 35 mph (55 km/h), push the
accelerator pedal about halfway down.
•Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
You will shift down to the next gear and have more
power.
Downshifting the transmission in slippery road conditions
could result in skidding, see “Skidding” underLoss of
Control on page 5-10.
3 (Third):This position is also used for normal driving.
However it reduces vehicle speed more than D (Drive)
without using the brakes. You might choose 3 (Third)
instead of D (Drive) when driving on hilly, winding roads,
when towing a trailer, so there is less shifting between
gears and when going down a steep hill.
You should use 3 (Third) (or a lower gear as needed)
when towing a trailer to minimize heat build-up and
extend the life of the transmission.
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2 (Second):This position reduces vehicle speed even
more than 3 (Third) without using the brakes. You
can use 2 (Second) on hills. It can help control vehicle
speed as you go down steep mountain roads, but
then you would also want to use the brakes off and on.
You may use this feature for reducing torque to the
rear wheels when you are trying to start the vehicle from
a stop on slippery road surfaces.
1 (First):This position reduces vehicle speed even
more than 2 (Second) without using the brakes. You can
use it on very steep hills, or in deep snow or mud. If
the shift lever is put in 1 (First) while the vehicle
is moving forward, the transmission will not shift into
first gear until the vehicle is going slowly enough.
Notice:Spinning the tires or holding the vehicle in
one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by the vehicle warranty. If you
are stuck, do not spin the tires. When stopping on a
hill, use the brakes to hold the vehicle in place.Tow/Haul Mode
Vehicles with an automatic transmission have a tow/haul
mode. The tow/haul mode adjusts the transmission
shift pattern to reduce shift cycling, providing increased
performance, vehicle control, and transmission
cooling when towing or hauling heavy loads.
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Turn the tow/haul mode on and off by pressing the
button, located to the right of the steering wheel on the
instrument panel. When tow/haul is on, a light on
the instrument panel cluster will come on.
SeeTow/Haul Mode Light on page 4-35for more
information.
Also see “Tow Haul Mode” underTowing a Trailer on
page 5-30for more information.
Grade Braking (Six Speed Automatic
Transmission)
The Grade Braking shift modes can be activated by
pressing the tow/haul button on the dash. While
in Range Selection Mode, Grade Braking is deactivated
allowing the driver to select a desired range of gears.
Grade Braking is only active while the Tow/Haul Mode is
selected and you are not in the Range Selection
Mode. See “Tow/Haul Mode listed previously and
Automatic Transmission Operation (Six Speed Automatic
Transmission) on page 3-27orAutomatic Transmission
Operation (Four Speed Automatic Transmission) on
page 3-32for more information on the Range Selection
Mode. Grade Braking assists in maintaining desired
vehicle speeds when driving on downhill grades
by automatically shifting to lower gears when the driver
desires to slow the vehicle by applying the brake.
This reduces wear on the braking system and increases
control of the vehicle.
Also seeTowing a Trailer on page 5-30for more
information.
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Cruise Grade Braking (Six Speed
Automatic Transmission)
Cruise Grade Braking operates only while cruise control
is engaged in Tow/Haul mode. Cruise Grade Braking
assists in maintaining desired vehicle speeds when
driving on downhill grades in cruise control by
automatically shifting to lower gears when the cruise set
speed is exceeded.
While in the Range Selection Mode (RSM) mode, cruise
grade braking is not available.
SeeAutomatic Transmission Operation (Six Speed
Automatic Transmission) on page 3-27orAutomatic
Transmission Operation (Four Speed Automatic
Transmission) on page 3-32.
Parking Brake
To set the parking brake, hold the regular brake pedal,
then push down the parking brake pedal.
If the ignition is on, the brake system warning light will
come on.
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